Vivitar was a distributor of photographic equipments established in 1938. Although there are thousands of Vivitar lenses (mostly manual focus) in the second hand market, Vivitar actually did not make any of these lenses themselves. They were all out-sourced to different manufacturers around the world and some of these companies (like Kiron and Schneider) are well known for their quality products while some others are not as good. That is probably the reason that you will hear one Vivitar user praises the optical quality of his/her lens while another one might say his/hers is the worst lens he/she has ever owned.
This makes buying and collecting used Vivitar lenses fun and also challenging. With the Internet and the Web, it is now easier to find out the origin and reviews of a particular Vivitar lens. However, simply type in the phrase “Vivitar 28mm f2.8” will not give you anything conclusive because they are probably more than ten different versions of 28mm f2.8 with the Vivitar brand printed on it. Thus, you need to distingusih them with the cosmetic differences (e.g. filter sizes, focusing rings) and/or the serial numbers. Some Vivitar lenses have standardized serial numbers and you might want to consult http://www.cameraquest.com/VivLensManuf.htm for further details.
The Compact 135mm f2.8 Automatic in this post was marketed by Vivitar starting in 1968. It belongs to a group of lenses marketed during the same time known to the collectors as the “Bright Band Family”. The name comes from the depth-of-field scale being a bright silver band positioned between the focusing ring and the aperture ring. Most lenses in Bright Band Family were descendents from an earlier group known as the “Chrome Nose Family” in the collector circle and were manufactured by Kino Precision (i.e. Kiron). However, the Compact 135mm is not one of them. It was introduced as a new technological advance in lens design and was probably made by Komine although no one yet can confirm its true origin.
Well, back to the lens itself, the Compact 135mm f2.8 is strongly built like most other lenses in the same era. It also has a built-in retractabe lens hood with a “shade coverage” appropiate to its focal length (most built-in lens hoods I have encountered are too short). However, it is by no mean “compact” in today’s standard. In fact, it is the largest 135mm lens I have ever owned. Its filter size of 62mm should probably give you a hint of its size. Optically, this lens is very good. It is sharp on par with my Tamron Adaptall-2 135mm f2.5 and gives pretty good contrast like the Canon FDn 135mm f3.5 despite its older coating technology. I bought this lens in order to replace my Korean made Pracktica 135mm f2.8 due to its better and more consistent (e.g. consistent sharpness with varied focal distance) optical quality. Below are two sample imges taken with the lens. The first one was shot in Ilford Delta 100 with focus at the brick wall of the building behind the traffic light and the second photo was shot in Ilford HP5+.